Electric machines such as traction motors generate heat which must be removed efficiently to prevent permanent damage to the motor. An internal fan is commonly used to cool the machine by drawing outside air over the motor coils. The air is drawn into the motor through openings in one end of the motor housing, and is blown out of the motor through the other end. However, there are spaces over which the air does not pass, isolating portions of the motor from the cooling air. This causes increased temperature rises in the machine and can cause overheating and shorter insulation life, which are undesirable. For this reason, there is a need for methods and apparatus for providing cooling air to otherwise isolated parts of the machine.
Accordingly, one object of this invention is to provide new and improved methods and apparatus for ventilating rotating electric machines.
Another object is to provide new and improved methods and apparatus for more evenly cooling electric machines.
Still another object is to provide new and improved methods and apparatus for ventilating electric machines which reduce overheating in isolated parts of the machine.
Yet another object is to provide new and improved methods and apparatus for ventilating electric machines by drawing outside air through both ends of the machine housing.